Flutter/外部ライブラリ/メール送信/flutter mailerのソースを表示

==flutter_mailerとは==
直でflutterからメール送信できるライブラリ

==公式==
https://pub.dev/packages/flutter_mailer

==インストール==
<pre>
dependencies:
  flutter_mailer: ^0.4.1+1
</pre>

==サンプル==
<pre>
import 'package:flutter_mailer/flutter_mailer.dart';
    final MailOptions mailOptions = MailOptions(
      body: 'a long body for the email <br> with a subset of HTML',
      subject: 'the Email Subject',
      recipients: ['example@example.com'],
      isHTML: true,
      bccRecipients: ['other@example.com'],
      ccRecipients: ['third@example.com'],
      attachments: [ 'path/to/image.png', ],
    );
    await FlutterMailer.send(mailOptions);
</pre>

==エラーが出てしまう==
<pre>
~/android/app/src/debug/AndroidManifest.xml:22:18-91 Error:
	Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from [com.android.support:support-compat:28.0.0] AndroidManifest.xml:22:18-91
	is also present at [androidx.core:core:1.0.2] AndroidManifest.xml:22:18-86 value=(androidx.core.app.CoreComponentFactory).
	Suggestion: add 'tools:replace="android:appComponentFactory"' to <application> element at AndroidManifest.xml:11:5-34:19 to override.
<pre>